Method for making hollow ice bodies

ABSTRACT

A hollow body of ice is formed by filling with water a mold having a cavity conforming to the desired shape of the body. The mold is then cooled for a time period sufficient to freeze only the peripheral portion of the volume of water filling the mold. The partially frozen body is then removed from the mold and a pair of opposed holes are punched through the ice layer to permit the entrained water to drain out, leaving a thin-walled shell of ice.

United States Patent 1 91 i 6/1964 Miller a a1. N

r COMPRESSOR [11] 3,721,103 Brandt et al. [45]March 20, 19 73 [54] METHOD FOR MAKING HOLLOW ICE 3,159,011 12/1964 7 BODIES I 3,095,260 6/1963 3,233,562 2 1966 [75] Inventors: William L. Brandt; Tommy E. 3,039,277 41962 Boston; Don E. Reed, Lebanon, Mo. 3,287,926 11 1966 [73] Assignee: Olin Corporation 3640O8l 2/1972 [22] Filed: June 15, 1970 Primary Examiner-William E. Wayner I [2]] AppL No: 46,277 $iIIOHrZIZyQZZnIaeIS R. Motsko, H. Samuel Kleser and [52] US. Cl. ..62/73, 264/302, 264/317, [57] ABSTRACT Int Cl 425/ A hollow body of ice is formed by filling with water a o o e s a 6 e 6 e I e "In". a [58] Flew of Search Z 264,28 of the body. The mold is then cooled for a time period 6 /302 25/437 290 sufficient to freeze only the peripheral portion of the volume of water filling the mold. The partially frozen [56] References cued body is then removed from the mold and a pair of op- UNITED STATES PATENTS posed holes are punched through the ice layer to per mlt the entrained water to drain out, leaving a thm- 720,482 2/1903 Richards ..264/3 17 walled shell of ice, 1,656,312 1/1928 Black 3,135,814 1 Claim, 10 Drawing Figures /0 l4 C ONDE N501? S TOR/4 G5 TA NK PATENTEDMAR20 I973 SHEET 1 [IF 7 INVENTORS WILL/AM L. BRANDT TOMMY E. BOSTON DON E REED Q N w.\\\ @8538 A A mowmmmsou Q N w w w ATTORNEY PATENTEDMARZOIBYS 3,721,103 I 'SHEEIEUFY W/LL/AM L. BRANDT TOMMY E. BOSTON DON E. REED ATTORNEY PATENIED HARZO 1915 'SHEET 3 OF 7 PATENTEDimzo ma SHEET u BF 7 INVENTORS WILL/AM L. BRANDT TOMMY E. BOSTON DON E. REED BY MM ATTORNEY PATENTEDmnazo ms 3.7211103 SHEET 50F 7 INVENTORS. WILLIAM L. BRANDT TOMMY E. BOSTON DON E. REED ATTORNEY PATENTEDmzo I975 SHEET 6 OF 7 &

G I Q9 M Q INVENTORS WILLIAM L. BRAND-T TOMMY E. BOSTON DON BREED MM 1. m,

METHOD FOR MAKING HOLLOW ICE BODIES This invention relates to a method and apparatus for making a hollow body, preferably of ice and preferably for use as a frangible target to be used in shooting galleries, target ranges, and the like.

In the past targets for shooting ranges, such as trap and skeet ranges, and the like, have been made from a variety of materials, such as glass, clay, compressed particulate material, and even compressed particles of ice. Such targets should possess sufficient strength so as to be easily handled, and yet should be sufficiently frangible to break when struck by a fraction of the total number of pellets fired at the target. A further desirable quality of such a target is the ability of the target to literally explode when struck by a shot charge thus leaving absolutely no question as to whether the target was or was not, in fact, hit by the shooter.

Ice has been found to be a particularly suitable material for use as a target since it possesses a degree of strength and resiliency sufficient to permit handling, and yet is sufficiently frangible to break easily. when struck by a fired shot charge. One further advantage attendant to the use of ice as a target lies in the fact that no clean up of the broken target fragments is necessary, since they merely melt. It has also been determined that targets of ice formed in the shape of hollow bodies, such as a hollow sphere of ice, will literally explode when struck by only one or two pellets from a charge fired at the target. Furthermore, the cost of producing targets in the form of hollow spheres of ice is a small fraction of the cost of producing similar glass targets, or the like.

This invention relates to a method and apparatus which are particularly useful for forming hollow bodies, preferably spheres, of ice for use as targets. The method of this invention broadly includes the steps of providing a mold having a spherical cavity and introducing into the mold a charge of water of sufficient volume to fill the mold cavity. The mold is then cooled so as to cause only the peripheral portion of the charge of water to freeze in place so as to form a spherical shell of ice which is filled with water. The wall thickness of the ice shell can be varied by varying the temperature to which the mold is cooled, and the time period at which the mold is maintained at the cooled temperature. After the shell of ice has been formed in the mold, the temperature of the mold is raised sufficiently to cause superficial surface melting to occur on the exterior of the ice so as to free the shell from the mold cavity wall. The mold is then opened and the shell of ice is pierced, preferably in two opposite locations so that the water in the shell will drain out. After the water has drained out, there remains a hollow shell of ice which can be used as a target.

The apparatus used to perform the method of this invention includes a mold which is subdivided into equal halves. There are preferably several molds associated in a bank so that a plurality of targets can be made during one operating cycle. Each mold half includes a main mold body which cooperates with the other half to form the mold cavity, and an outer shell or jacket which is mounted on the mold body and spaced apart therefrom to provide a space into which coolant is circulated to freeze the charge of water. A track is provided beneath each mold so that the frozen spheres can drop out of the molds and onto the track. The spheres are then taken to a punching station where they are punctured and the entrained water is drained from them. They are then taken to a launcher, storage area, or other area where they are used as targets.

The apparatus further includes a refrigeration system which preferably utilizes a coolant such as Freon 12 to cool the molds and to defrost the frozen spheres from the mold cavity wall before the spheres are removed from the molds. The refrigeration system includes a compressor having suction conduits leading from the mold halves to the suction side of the compressor. A conduit extends from the head side of the compressor to a condenser and thence to a storage or receiver tank. A further conduit extends from the receiver tank to an expansion valve, and from the expansion valve to a distributor which has conduits leading therefrom to each of the mold halves. Yet another conduit extends from the head side of the compressor to the distributor, the latter conduit being selectively opened by a solenoid valve to circulate warm gases from the compressor head to the molds for the defrost cycle.

The apparatus still further includes a water system which has a storage tank and a pump associated therewith. A conduit leads from the storage tank to a precooler which precools the water before it is pumped to the molds. The water which is drained from the frozen bodies is collected in a trough and returned to the storage tank for reuse.

It is therefore an object of this invention to provide a method for forming a hollow body of a frozen liquid.

It is a further object of this invention to provide a method for forming a hollow body of ice for use as a target.

It is yet another object of this invention to provide an apparatus for molding a hollow body of ice for use as a target.

It is still another object of this invention to provide an apparatus of the character described which apparatus includes a mold for forming a hollow body of ice filled with water and means for puncturing the body to drain the water therefrom.

These and other objects and advantages of the invention will become readily apparent from the following detailed description when taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a schematic representation of the refrigeration system preferred for use with the apparatus of this invention;

FIG. 2 is a schematic representation of the water supply system preferred for use with the apparatus of this invention;

FIG. 3 is a perspective view of the apparatus of this invention showing several molds arranged in a bank and showing the puncturing stations and tracks for moving filled bodies from the molds to the puncturing stations;

FIG. 4 is a top view of a portion of the apparatus of FIG. 3 showing a pair of adjacent molds and the pistons which are secured to half of each of the molds;

FIG. 5 is a vertical sectional view of one of the molds showing the refrigeration and defrost jacket and showing the mold as it appears when full of water which has been peripherally frozen to form a hollow body of ice;

FIG. 6 is a side view partially in section showing the mold halves as they appear when opened to release the hollow ice body, and showing the movement of the ice body from the mold to the puncturing station;

FIG. 7 is a side view similar to FIG. 6 but showing the operation of the apparatus as the ice body is punctured to drain water from the interior of the body;

FIG. 8 is a sectional view of the needle used to puncture the ice bodies, the hollow interior of the needle being shown and the preferred form of the cutting edge of the needle being shown;

FIG. 9 is a side view similar to FIGS. 6 and 7 but showing the drained body being dropped onto a ramp for movement to another station for use or storage; and

FIG. 10 is composite drawing showing the various cam profiles which are used in the timer mechanism for controlling the various pieces of equipment during the operating cycle of the apparatus.

Referring now to FIG. 1, the refrigeration equipment preferred for use with this invention is shown schem atically. The refrigerant preferred for use with this invention is Freon l2, and it is circulated through a closed system including a compressor 2 having a suction or inlet side 4 and a head or outlet side 6. A conduit 8 leads from the compressor head side 6 to a condensor 10. A solenoid operated valve 12 is disposed in the conduit 8 between the compressor 2 and condensor 10, the valve 12 being normally operative to permit refrigerant to flow from the compressor 2 to the condensor 10. A conduit 14 leads from the condensor 10 to a storage tank 16, and a further conduit 18 extends from the storage tank 16 to an expansion valve 20. The expansion valve 20 permits the pressurized liquid from the tank 16 to expand into a gas thus lowering the temperature thereof. The expansion valve 20 is preferably a Sporlan 1% I-I.P. C charge head valve, manufactured by the Sporlan Valve Co., St. Louis, Missouri. A conduit 22 extends from the expansion valve 20 to a distributor 24, which is preferably a Sporlan distributor having an appropriate number of circuits, e.g., one for each mold half, and having a hot gas defrost inlet.

A number of conduits 26 extend from the distributor 24 to the molds 28, it being understood that for reasons of simplicity that, although only one conduit 26 is shown for each mold 28, there are in fact a pair of conduits leading from the distributor to each mold, one of each of the pair being connected to each half of the mold. A further number of conduits 30 extend from each mold 28 to a collector 32 which communicates with a conduit 34 in turn connected to the suction side 4 of the compressor 2 to complete the circuit. A further conduit 36 extends from the solenoid operated valve 12 to the distributor 34, the latter conduit 36 being used in the defrost portion of the cycle, as will be explained in greater detail hereinafter.

FIG. 2 schematically shows the water system which is preferred for use with this invention and which includes the pump 42 operates constantly to circulate water from the storage tank 38 to the pre-cooler 46 and return to maintain the water supply at a favorably cool temperature. A conduit 54 extends from the valve 52 to each of the molds 28 so that when the valve 52 is opened, water will be pumped into each mold cavity. A drainage trough 56 collects water drained from the ice shells and a conduit 58 returns the drained water to the storage tank 38.

Referring now to FIG. 3, a preferred form of the apparatus of this invention is shown. The apparatus includes a housing 60 in which are disposed the compressor, condensor, refrigerant storage tank, the water storage tank, water pump, water pre-cooler and other elements shown schematically in FIGS. 1 and 2. A conventional timer mechanism having rotating cam discs for controlling various phases of the method cycle is mounted in a box 62 disposed on the housing 60. The timer control cam profiles will be set forth in greater detail hereinafter.

A mounting plate 64 is secured to the front of the housing 60 and a plurality of forwardly extending guide plates 66 are connected to the mounting plate 64. A frontal plate 68 is secured to the guide plates 66 and extends across the front of the apparatus to provide a frame to which the front half of each of the molds 28 is secured. In the specific embodiment shown in FIG. 3, there are four molds 28 mounted on the frontal plate 68 and guide plates 66, there being one mold 28 between each pair of adjacent guide plates 66. It is understood, however that any number of molds can be included in the apparatus without departing from the spirit of the invention.

A pair of supporting arms 70 are pivotally mounted to each end of the mounting plate 64, the arms 70 being arranged for pivotal movement about pins 72. A transverse base plate 74 is secured to each of the supporting arms 70 and an inclined ramp 76 is connected to the base plate 74 forward thereof. A plurality of pads 78 of spongy resilient material are disposed on the top of the base plate 74 and a plurality of inclined guiding members 80 are secured to the base plate 74 and extend upwardly and rearwardly therefrom. Each guiding member 80 preferably includes a tubular side part 82 and a tubular bottom part 84 connected together to provide a track along which targets can be moved from the molds to a puncturing station. Thus, there is one guiding member 80 disposed below each mold 28. A plurality of recessed cavities 86 are formed in the spongy pads 78 at the lower end of each guiding member 80.

A plurality of L-shaped brackets 88 are mounted on the plate 68 and a pad 90 of spongy material is secured to the bottom surface of the horizontal leg of each of the brackets 88. A tube 92, through which passes a stream of pressurized air from a tank (not shown) disposed in the housing 60, extends across the front of the plate 68 and is connected to each of the brackets 88 by means of a plurality of tubular fittings 94, the purpose of the pressurized air stream being set forth in more detail hereinafter.

A pair of fluid actuated cylinders 96 and 98 and associated pistons 100 and 102 respectively, are connected in series, the piston 100 being pivotally connected to the plate 74, and the piston 102 being pivotally connected to a bracket 104 which is secured to the plate 68. The pistons 100 and 102 are operative to raise and lower the plate 74 in a manner set forth more clearly hereinafter.

A plurality of electrical resistance heating elements 106 are mounted above each of the water inlet fittings 108 to which the water conduits 54 are connected. The heating elements 106 are periodically actuated to prevent ice from freezing up and closing the water inlet for each mold.

Referring now to FIGS. 4 and 5, the mold assemblies 28 each include a pair of cylindrical housings 110 and 112. The housing 110 is clamped between the frontal plate 68 and a first face plate 114 by means of a plurality of bolts 116, and the housing 112 is clamped between a second face plate 118 and a rear plate 120 by means of a plurality of bolts 122. A piston 124 is secured to the rear plate 120 so that movement of the piston 124 results in movement of the cylinder 112 and all parts secured thereto. A guide arm 126 is secured to the cylinder 112 such that the ends of the guide arm 126 rest on the top surface of the guide plates 66 to guide movement of the cylinders 1 12.

Each of the face plates 114 and 118 are counter bored at 128 and 130 respectively, and the plate 114 includes an air bleed port 132. The mold is formed with two substantially hemispherical parts 134 and 136, each of which includes a flange 138 and 140 respectively which are seated in the counter bores 128 and 130 and secured to the face plates 114 and 118 by brazing or welding. The mold halves 134 and 136 are preferably copper for desirable heat transfer properties, but may be formed from other materials, such as aluminum, or the like without departing from the inventive concept. The mold halves 134 and 136 combine with the inner faces of the face plates 114 and 1 18 to form the mold cavity 142. As shown in FIG. 5 the mold cavity. 142 has been filled with water and the peripheral portion of the water has been frozen to form a sphere of ice 144. A pair of mold jackets 146 and 148, of substantially hemispherical configuration and having flanges 150 and 152 disposed in the counter bores 128 and 130 respectively are secured by brazing, welding, or the like, to face plates 114 and 118 respectively. The outer surfaces of the mold halves 134 and 136 and the inner surfaces of the mold jackets 146 and 148 are spaced apart to form substantially hemispherical coolant chambers 154 and 156 about the mold. The coolant conduits 26 extend through apertures 158 and 160 in the jackets 146 and 148 respectively and open into the lower portion of the chambers 154 and 156. Similarly, the coolant conduits 30 extend through apertures 162 and 164 in the jackets 146 and 148 respectively and open into the upper portion of the chambers 154 and 156. The water inlet fitting 108 extends through apertures 166 and 168 in the mold jacket 146 and the mold half 134 and opens into the mold cavity 142. The space between the mold jackets 146 and 148,

v and the cylinders 110 and 112 is filled with an insulation material 170 of conventional composition, such as a mixture of cork and tar, or the like.

It has been determined that an ice target in the form of a hollow sphere of ice having an outside diameter of about 2% inches, and weighing about 32 grams is preferable for launching or for other use as a target. Such an ice sphere, 144 as shown in FIG. 5, is formed in the following manner. The pistons 124 are actuated so as to move the face plates 114 and 118 into abutting position as shown in FIG. 5, and the valve 52 is opened so that a charge of about 140 grams of water precooled to a temperature of 34-36 F. is injected through the conduits 54 and fittings 108 into the mold cavities 142, 140 grams of water being the amount needed to substantially fill a mold cavity having a diameter of about 2% inches. Air entrapped in the mold cavity 142 is bled off therefrom through the port 132 as the water fills the mold cavity. When the mold is closed by actuating the pistons 124, the expansion valve 20 is opened to permit liquid refrigerant to pass from the storage tank 16 into the valve 20 where the liquid is converted to a gas with an attendent drop in temperature. The cooled gas then passes into the distributor 24 and through the conduits 26 and thence into the refrigeration chambers 154 and 156. The mold halves 134 and 136 are thus cooled to a temperature preferably within the range of about 2 to 10 F for a time period of about 1 minute and 30 seconds, the most preferred mold temperature being 6 F. By cooling the mold to the above-noted preferred temperature range for 1 minute and 30 seconds, the periphery of the charge of water contained in the mold cavity 142 will freeze to form a sphere of ice 144 having a wall thickness of about one-eighth of an inch, however the remainder of the water charge will not freeze, but will remain in the liquid state. After the freeze cycle of l minute and 30 seconds has expired, the valve 12 is actuated to pass warm gases from the compressor 2 through the conduit 36 and into the distributor 24, and thence into the conduits 26 to the refrigeration chambers 154 and 156. The warm gases thus raise the temperature of the mold halves 134 and 136 to within the range of about 35 to 45 F., the preferred defrost mold temperature being 40 F, so as to cause exterior surface melting to occur on the ice sphere 144 to prevent the latter from adhering to the mold cavity walls when the mold halves 134 and 136 are separated. The defrost cycle continues for a time period of about 40 seconds, at approximately the end of which time period the mold halves 134 and 136 are separated by actuating the piston 124, as shown in FIG. 6. Also during the defrost cycle, the heaters 106 are briefly actuated to melt any freezing which may occur in the water inlet fitting 108,

thus clearing the inlet for the next cycle.

Referring to FIG. 6, when the piston 124 moves the cylinder 112 and its associated mold half away from the cylinder 110 and its associated mold half to open the mold, the ice sphere 144 falls onto the inclined guiding member and rolls down therealong untilit settles into the recessed cavity 86 on the spongy pad 78. The spongy pad 78 includes a passage 79 which extends downwardly from the cavity 86 and in which is mounted a hollow needle 81. A similar needle 83 is mounted in a passage through the upper spongy pad 90. The needles 81 and 83 are similar in construction, and are shown in section in FIG. 8. Each needle includes a shank portion 87 and an enlarged externally threaded portion 89. A central bore 91 passesthrough the shank 87 and threaded portion 89, with the shank end of the bore 91 being angularly beveled as at 93 to form an annular sharp cutting edge which is used to pierce the ice spheres. The bore 91 in the upper needle 83 is used to pass a stream of air from the conduit 92, and the bore 91 in the lower needle 81 is used as a passage through which water is drained from the ice spheres. Water is also drained through the passage 79 and aligned holes 73 drilled through the plate 74. It is noted that when the supporting arm 70 is in its normal position shown in FIG. 6, the spongy pad 78 preferably is sufficiently rigid to prevent the ice sphere 144 from touching the lower needle 81. As shown in FIG. 6, the ice sphere 144 is now ready to be pierced and drained of internal water.

The sphere 144 is punctured by actuating the piston 102 to cause the support arms 70 to pivot upwardly about the pins 72 thereby moving the sphere 144 toward and against the needle 83 and pad 90, as shown in FIG. 7. The pads 78 and 80 are thus deformed and the needles 81 and 83 are caused to puncture the sphere 144 at diametrically opposed locations. The sphere 144 is held in the position shown in FIG. 7 for a predetermined period of time while air is fed through the bore of the upper needle 83 into the interior of the sphere 144 to force the entrained water to drain through the bore in the lower needle 81 and through the passage 70 and holes 73. After the water has drained from the sphere 144, the piston 102 is caused to return the support arm 70 to its original position shown in FIG. 6, with the pads 90 and 78 flexing to disengage the needles 81 and 83 from the sphere wall. The piston 100 is then actuated to cause the support arms 70 to pivot downwardly about the pins 72 to the position shown in FIG. 9 thus causing the drained sphere 144 to be dumped from the pad 78 onto the inclined ramp 76 along which the sphere 144 rolls to a further station, which may be a station for storing the ice targets, or for presenting them to be fired at, or the like. After the targets 144 are dumped onto the ramp 76, the arms 70 are returned to their normal positions by the piston 100 to be ready to receive other spheres from the molds.

FIG. 10 is a schematic representation of the cam profiles used on the cam discs in the timer assembly 62 showing how the various operations are coordinated in an operational cycle which lasts for a time period of 2 minutes and 10 seconds, the time period being presented so that the beginning and ending of each operation can be noted at points which correspond to percentages of the total time period.

It will be readily appreciated that the method and apparatus of this invention are extremely useful for forming hollow bodies which can be used for targets, and which can be made of ice. By placing the molds in a coordinated bank, any number of targets can be made in one operational cycle. By molding the targets from ice, the resulting article is easy to handle possesses desirable frangibility when hit with a fired projectile, is extremely inexpensive to make, and presents no problem relating to clean up of broken target fragments.

Since many changes and variations of the disclosed embodiments of the invention may be made without departing from the inventive concept, it is not intended to limit the invention otherwise than as required by the appended claims.

What is claimed is:

1. A method of making a hollow, frangible body of ice comprising the steps of:

a. cooling a charge of water to a temperature in the range of about 34 to about 36 F;

b. filling a mold cavity with said charge of cooled water;

c. cooling said mold cavity to a temperature in the range of about 2 to about l2 F. for a period of about 1 minute and 30 seconds to form a thinwalled peripheral shell of ice about a central core of water within said mold cavity;

. warming said mold cavity to a temperature in the range of about 35 to about 45 F for a period of about 40 seconds to effect external surface melting of said shell of ice; and

e. removing said shell of ice and core of water from said mold cavity; and

f. forming diametrically opposed openings in said shell of ice to effect drainage of said core of water from said shell of ice.

l =9 1 III 1 

1. A method of making a hollow, frangible body of ice comprising the steps of: a. cooling a charge of water to a temperature in the range of about 34* to about 36* F; b. filling a mold cavity with said charge of cooled water; c. cooling said mold cavity to a temperature in the range of about 2* to about 12* F. for a period of about 1 minute and 30 seconds to form a thin-walled peripheral shell of ice about a central core of water within said mold cavity; d. warming said mold cavity to a temperature in the range of about 35* to about 45* F for a period of about 40 seconds to effect external surface melting of said shell of ice; and e. removing said shell of ice and core of water from said mold cavity; and f. forming diametrically opposed openings in said shell of ice to effect drainage of said core of water from said shell of ice. 